Mechanical lead pencil



C C HARRIS ETAL MECHANICAL LEAD PENCIL Filed Jan. 24, 1950 April 7, 1953 Patented Apr. 7, 1953 f UNITED STATES PATENT. f OFFICE i gi633827i1. fr' v '-i V MECHANICAL LEAD PENCIL l c Carl C. Harris, Orange, andBurton Newton',l Athol, Mass., ass'ignors to *The iSlcncil- Coi; Orange, Mass.,r af corporation of Massachusetts Application Januar'yum, 1950, serial No; 140,248

l This invention relates vto improvementsV in mechanical lead pencils comprising a straight tubular body with a convergingly ltapered* end and having lead-engaging and propelling and retracting mechanism,v mounted axially therein, with means for extending the lead beyond Vthe tapered end of the barrel for use in writing. In many pencils of this type the pressureY applied-to the extended end of the lead, when the pencil is in` use, Voften forces the lead into the barrel "of the pencil so that the tapered end of the pencil alone engages the surface to be marked thereby preventing proper inscription by the lead upon such surface.

One object of the invention is to provide means for preventing such retraction of the lead into the barrel. Y

A further object ofthe invention is to provide a pencil of this character with interengageable means respectively on the barrel and the leadpropelling means'for'preventin'g the lead from being forced into the barrel of the pencil by pressure applied to the end thereof, but which will also permit disengagement 4of the interengageable members to venable the vlead-propelling means to extend the lead beyond the tapered end of the barrel or to retract it within the barrel.

A further object of the invention is to provide 6 claims. (c1. 12o-+18) resilient means acting upon the lead-propelling mechanism which will supplement the action of More specifically the invention relates torim provements in thin writing pencils.A ofthe type disclosed generally in Reissue Patent No. 20,481

granted August 24, 1937, and to the embodiment therein of propelling mechanism having means to prevent undesirable retraction ofthe lead into the pencil body by pressure applied` to the end of the lead when extended beyond the tapered end portion of the barrel.

These and lother objects and features of the invention will more fully appear from the following description and the accompanying drawings and will be particularly pointed out in the claims. Preferred embodiments of the invention are shown in the accompanying drawings, in which,

Fig. 1 isan enlarged side view of a pencil.

embodying the invention;

Fig. 2 is a longitudinal.sectionall view of the.

pencil shown inFig. l onta stilllarger scale;-

'Figf isa transverse sectional view Von line SfSFs. 2:."

Fig. 4 is aview of a U-shaped spring for frictionally applying pressurevto the rotatable member shown in Fig; 2; Y n Fig. 5 is a detail top view, andFig. 6 a side elevation; of the collar'for actuating the rotatable member; j

Fig. 'Tis Ya detail view'of the' lead-propelling member shown'in Fig. 2;

, Fig. 8A is a detaill View of shown'in Fig. 2; Y

Fig. 9 is a viewcorresponding to the lower portion of Fig. 2 with theV parts in extreme leadexpelling position. g

The invention is embodied in a thin mechanical lead pencil having a body or barrel of generally rectangular form, preferably of about 1/2" in width-and 1a-6" in thickness; and of any desirable length, 'and- -with the sidesI and 2 having opposite longitudinally extending Y semi-circular corrugations yil and 4 extendingV approximately from the center of the length of thepencil to the tip thereof, and narrow-edges 5 and 6 integral withV and uniting the sides of the pencil. The edges'of the barrel at one end Yconvergingly merge into the-corrugationsS and 4 and a conoidal tip 'I having ashankis mounted in the tapering end of the barrel and forms a continuation thereof. The tip is providedv with a lcentral axial bore 9 formigfaguideway for the lead of the pencil and having a cup-shaped upper end Iii which serves to direct the lead'into the guidewa'y if it is withdrawn beyond 'the upper end of the shank.`r`

A cylindrical sleeve I I is rotatably mounted in the socket formed byrthecorrugations 3 and 4 andextends longitudinally axially of the barrel and is provided with -a helicalY slot I2. A cylindrical lead-engaging and propelling member I3 is slidably mounted'in the sleeve II and is pro- Vi'ded'with a laterally extending arm I4 which engages the helical slot I2 in the sleeve II. The lower endof thezpropelling member-I3 is provided witha 'short slit I5 to enable the walls thereof frictionally to embrace the 'upper end of the lead sc thatupon upward movement of the propelling member the lead will be retracted into the barrel ofthe pencil.

An expelling rod I 6 is slidably mounted in the cylindrical lead-propelling member I3 and is provided adjacent its upper end with an arm I'I exthe expelling rod tending into. the helical slot I2 of--the leadpropellingrnember and I'Lof this expelling'rod the upper end of the sleeve II andffi's of sum1' cient diameter to t Within the recesses I8 and extends slightly through the'openings" thereof.' The collar I9 desirably is providedfwit'hafknurled surface 2l to enable it to be readily grasped vto rotate the sleeve Il.

The upper end of this collar I9 is provided with serrations 25 engageable with the adjacent edges of the upper Wallsfof the recesses I8. The collarV is sufficiently'shorter thanthe: length of the recesses I8- so thatr when, moved downward to seat on the bottom' ofl therec'essesthel serrations on the collar'arereleasdrom engagement' with the edges of the upper walls of tl'ierecesses,l Thus the collar may beifreely'rotated in turn to rotate Ythe heli'c'ally slotted sleeve aridn thereby` propel or retract the leadl as desired. But any pressure applied to" the end of th'e'lead` in writing, or otherwise, suiciently to retract the lead slightly will at once' press the helically`.slotted.

sleeve upward, the serrations willfcom'e intofe`n`" gagement with the edge'sfofk the recesses, and,v

thus lock the sleeve against rotation andfprevntf retraction of the lead.l This isan vin'ip'ortant Vfea'- ture because, it not" infrequentlyfha'ppns in pencils Vof this type, `especially the parts are slightly loose o r Worn,l that eve'n normalf writing.-

edges of the barrel and has 'reversely curved.-

lovver ends 24 which frictionally engage the cylindrical portion 22 of the propelling sleeve.

spring functions tolsecurea permanent constantA slight friction on the solid cylindrical'seetion 22 of therotary sleeve Il sothat the collar I9 will turn the sleeve I I in either thefdirectio'rrtopropelv or the direction to retract the leadwithauniform smooth action. This spring also facilitatesthe assembly of the parts of the pencil because'it enables the various parts to be made with ai slight looseness of fit and thenrapidly and accurately positioned in the barrel with the insertion of thel spring from the top over the section 22holding the parts centered and. under the friction described.

The lead-engaging and propellingy member I3 is provided with a slot 5I- extending from4 the,

arm M to ak closed portion4 5,0 at the upper. end.

The arm I'I of the expelling member IIIV projectsV through this slot and'isprovided with a shorter section 52 riding on the slot 5IY softhatthe longin substantiallyv as shown Fig'. 2y the-lead isfin serted through the bore Sf in the tipandfr'c'ed inwardly until it enters the slitted end of the lead-propeling member I3 and is grasped thereby. The propeling and retracting of the lead in the use of the pencil then takes place in the usual manner by rotating the collar I9. When the lead is worn out and is to be entirely expelled the parts are moved-into substantiallyV the lposition shown in Fig. 9.' In this position the sleeve II is rotated preferably until the arm I4 passes out from the helical slot of the sleeve I I and engages the upperend of the shank 8 of the tip. Slight continued-rotation of the sleeve then brings the expelling-,member- IB- down until the section 52 engagesthe-arn I *4 2 and in this position the end dftheexpeiungvmemter Is is slightly outside of the tip 'land the lead entirely discharged. On the-reverseA rotationl of the sleeve the expelling member IE moves upward until it engages the shoulder 50 whereuponthe arms I'I and I4 are spaced apart tocorrespond with, the pitch ofthe helical slot andthe partsare' ready for the receptioof' the new man 'and for operation inthe usualmanner.'V 'o l"Ihe hollow upper end ofthe barrelprovidesa socket into which. a` holderA for an eraser 2,1 may be inserted, the holder 26v desirably being.Y provided with a rib, 28 adapted toY abut against. the end ofthe barrel.

It willbe understood; that the embodimentv of the invention shown andv described herein is ofan illustrative character, and that various changes in form; construction and arrangement of parts may be made Within the spirit' andscope of: the following claims.

Having thus'descr'ibed the invention, what is claimed as new, and desired to be securedicy-Letl-A t'ers Patent, is:

l. A thin mechanical lead pencil having ai rectangular barrel of rigidi material provided with aconoidal tip and' narrowlyspaced'l parallel sider Walls having, intermediate of theirj length registering recesses opening. at' the sides, a heli? `cally. slotted sleeveV rotatabl'ymount'ed'in and 'extending longitudinally'bf said barrel, lead-pfo-l peu'ing `meansl-lsiidab1y mountedfmsaid sieeve held against rotation with respectA toythe, barrel and .having means,l engaging the helical slotv in said sleeve, a` cylindrical collar flxedly mounted` on said sleeve extending into andv through the recesses in said barrel, the said collar actingwheny rota-ted in onedirection to extendf the end of-the lead beyondthebarrel tipv to writingv position, and. normally separated interlocking? means on said collar and barrel movedl into positive interlocking engagement to. lock'Y said'sleeve, and collar against reverse rotation byj'pre'ssure applied to the extended endof-the lead.

2. A mechanical lead pencilv having a hollow barrel. providedl vvithan conoidal tip andrwithl registering recesses open' at fthe sides of. thef barrel intermediate its length,Y a helically'k slotted sleeve rotatably mounted inA and extending longitudinally of said barrel, a tubularv lead-propelling' and gripping means slidably mounted in said sleeve held againstA rotation with' respect to i'the bar-rel andi having means engaging the helical slot ini saidQslee've, a cylindrical-collar of less length than' thatA of said recesses xedl-y" mounted on said sleeve with its periphery extending through the recessesthe saidl collar acting when rotated in i andbarrell'movedfinto positive interlocking eri-y gagement to lock said sleeve and collar against reverse rotation by pressure applied to the extended end of the lead.

3. A mechanical lead pencil as defined in claim` 2, in which the said interengaging means comprises a serrated surface on the upper end of said collar adapted positively to engage an adjacent upper wall of the recesses in said barrel.

4. A mechanical lead pencil as defined in claim 3, in which the serrated upper end of the collar is disengageable by slight longitudinal downward movement from the recess Wall to permit reverse 'rotation of the sleeve to retract the lead.

5. A thin mechanical lead pencil having a conoidal tip and a rectangular hollow barrel of thin rigid material with narrowly spaced side walls provided centrally with complementary longitudinal semi-cylindrical corrugations having in termediate of their length registering rectangular recesses open at the sides, the sides of the barrel convergingly merging from the edges into said corrugations, lead-propelling mechanism comprising a cylindrical helically slotted sleeve rotatably mounted in said corrugations having a solid upper longitudinally ribbed section registering with said recesses and a smooth cylindrical section above said ribbed section, a lead-engaging and propelling member slidably mounted in said sleeve having an arm engaging the helical slot of the sleeve, a knurled collar of slightlfyr shorter length than that of said recesses fxedly secured to the ribbed section of said sleeve and having its periphery extending through lthe openings of the recesses in said barrel, the said collar acting when rotated in one direction to extend the end of the lead beyond the barrel tip to writing position, serrations in the upper end of the collar acting when undue pressure is applied to the extended end of the lead to engage the upper edge of the adjacent wall or walls of the recesses and thereby prevent reverse rotation ci said sleeve and Withdrawal of the lead, and a U-shaped spring having its loop mounted in the edges of the barrel and portions of its legs frictionally ernbracing the smooth cylindrical section of the slotted sleeve acting to maintain said sleeve in proper axial alinement within said barrel and to supplement accurate adjustment of the lead.

6. A thin mechanical lead pencil as defined in claim 5, in which the lead-engaging and propelling member is of tubular form having a slitted lower end to engage the lead and a leaduejecting rod slidably mounted therein and provided with an arm extending into the helical slot in the sleeve well above the arm of the lead-engaging and propelling member.

CARL C. HARRIS. BURTON E. NEWTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,472,970 Fischer Nov. 6, 1923 1,488,385 De Witt Mar. 25, 1924 1,697,437 Stout et al Jan. 1, 1929 1,892,145 Guyot Dec. 27, 1932 1,910,552 Lavoie May 23, 1933 2,058,291 Belcher Oct. 20, i936 2,087,519 Lynn July 20, 1937 2,116,136 Beisang May 3, 1938 2,161,889 Schaefer June 13, 1939 

